Prozone phenomenon is responsible for-
Correct Answer: False negative test
Description: Ans. is 'a' i.e., False negative testo The amount of precipitate formed is greatly influenced by the relative proportions of antigens and antibodies.o Precipitation occurs most rapidly and abundantly in the zone of equivalence in which the antigen and antibody are present in optimal proportions.o If increasing quantities of antigens are added to the same amount of antiserum in different tubes and the amounts of precipitate in different tubes are plotted on a graph, the resulting curve will have three phases :Antigen - antibody reaction||||Ascending partPeakDescending part|||Prozone or zone of antibody excessZone of equivalencePost zone or zone of antigen excesso Prozone phenomenon causes false negative serological tests because overwhelming antibody titres interfere with the proper formation of the antgen- antibody lattice network necessary to visualise positive test.o To prevent this, several serum dilution should be testedo Prozone phenomenon is seen in :i) Brucellosisii) Syphilis- In secondary syphilis or with HIV infection.
Category:
Microbiology
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